1 5667 105 SFRP TUMOUR SUPPRESSOR GENES ARE POTENTIAL PLASMA-BASED EPIGENETIC BIOMARKERS FOR MALIGNANT PLEURAL MESOTHELIOMA. MALIGNANT PLEURAL MESOTHELIOMA (MPM) IS ASSOCIATED WITH ASBESTOS EXPOSURE. ASBESTOS CAN INDUCE CHRONIC INFLAMMATION WHICH IN TURN CAN LEAD TO SILENCING OF TUMOUR SUPPRESSOR GENES. WNT SIGNALING PATHWAY CAN BE AFFECTED BY CHRONIC INFLAMMATION AND IS ABERRANTLY ACTIVATED IN MANY CANCERS INCLUDING COLON AND MPM. SFRP GENES ARE ANTAGONISTS OF WNT PATHWAY, AND SFRPS ARE POTENTIAL TUMOUR SUPPRESSORS IN COLON, GASTRIC, BREAST, OVARIAN, AND LUNG CANCERS AND MESOTHELIOMA. THIS STUDY INVESTIGATED THE EXPRESSION AND DNA METHYLATION OF SFRP GENES IN MPM CELLS LINES WITH AND WITHOUT DEMETHYLATION TREATMENT. SIXTY-SIX PATIENT FFPE SAMPLES WERE ANALYSED AND HAVE SHOWED METHYLATION OF SFRP2 (56%) AND SFRP5 (70%) IN MPM. SFRP2 AND SFRP5 TUMOUR-SUPPRESSIVE ACTIVITY IN ELEVEN MPM LINES WAS CONFIRMED, AND LONG-TERM ASBESTOS EXPOSURE LED TO REDUCED EXPRESSION OF THE SFRP1 AND SFRP2 GENES IN THE MESOTHELIUM (MET-5A) VIA EPIGENETIC ALTERATIONS. FINALLY, DNA METHYLATION OF SFRPS IS DETECTABLE IN MPM PATIENT PLASMA SAMPLES, WITH METHYLATED SFRP2 AND SFRP5 SHOWING A TENDENCY TOWARDS GREATER ABUNDANCE IN PATIENTS. THESE DATA SUGGESTED THAT SFRP GENES HAVE TUMOUR-SUPPRESIVE ACTIVITY IN MPM AND THAT METHYLATED DNA FROM SFRP GENE PROMOTERS HAS THE POTENTIAL TO SERVE AS A BIOMARKER FOR MPM PATIENT PLASMA. 2017 2 2090 34 EPIGENETIC DYSREGULATION OF THE WNT SIGNALLING PATHWAY IN CHRONIC LYMPHOCYTIC LEUKAEMIA. BACKGROUND: WNT SIGNALLING HAS RECENTLY BEEN IMPLICATED IN THE PATHOGENESIS OF CANCER. METHODS: THIS STUDY INVESTIGATED THE ACTIVITY OF WNT SIGNALLING IN PERIPHERAL BLOOD CHRONIC LYMPHOCYTIC LEUKAEMIA (CLL) LYMPHOCYTES, AND THE METHYLATION STATUS OF SEVEN SOLUBLE WNT ANTAGONIST GENES, INCLUDING WIF1, DKK3, APC, SFRP1, SFRP2, SFRP4 AND SFRP5, BY USING METHYLATION-SPECIFIC PCR IN THE PERIPHERAL BLOOD CLL LYMPHOCYTES AND BONE MARROW SAMPLES OF PATIENTS WITH CLL AT DIAGNOSIS. RESULTS: IN THE PERIPHERAL BLOOD CLL LYMPHOCYTES, CONSTITUTIVE ACTIVATION OF WNT SIGNALLING WAS DETECTED, ASSOCIATED WITH HYPERMETHYLATION OF THE SOLUBLE WNT INHIBITOR GENES. IN THE DIAGNOSTIC CLL MARROW SAMPLES, METHYLATION OF THE SEVEN GENES WAS DETECTED IN UP TO 36.4% OF SAMPLES. MOREOVER, 23 (52.3%) PATIENTS HAD METHYLATION OF AT LEAST ONE OF THE SEVEN GENES, OF WHOM 14 (60.8%) HAD METHYLATION OF TWO OR MORE WNT INHIBITOR GENES. APART FROM AN ASSOCIATION OF ADVANCED AGE WITH DKK3 METHYLATION, THERE WAS NO ASSOCIATION OF GENE HYPERMETHYLATION WITH EITHER CLINICAL CHARACTERISTICS (INCLUDING AGE, GENDER, LYMPHOCYTE COUNT AT DIAGNOSIS, RAI STAGE AND POOR-RISK KARYOTYPE) OR SURVIVAL. CONCLUSION: WNT SIGNALLING IS CONSTITUTIVELY ACTIVATED IN CLL B LYMPHOCYTES IN ASSOCIATION WITH METHYLATION OF MULTIPLE SOLUBLE WNT ANTAGONIST GENES. METHYLATION OF THESE SOLUBLE WNT ANTAGONIST GENES, OCCASIONALLY MULTIPLE GENES, IN PRIMARY CLL MARROW SAMPLES SUGGESTS AN IMPORTANT ROLE IN CLL PATHOGENESIS. MOREOVER, THIS STUDY UNDERSCORED THE IMPORTANCE OF STUDYING METHYLATION OF A PANEL OF, BUT NOT INDIVIDUAL, GENES REGULATING A CELLULAR PATHWAY. 2008 3 1211 38 CPG ISLAND METHYLATION AND EXPRESSION OF THE SECRETED FRIZZLED-RELATED PROTEIN GENE FAMILY IN CHRONIC LYMPHOCYTIC LEUKEMIA. B-CELL CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) IS CHARACTERIZED BY A CLONAL ACCUMULATION OF MATURE NEOPLASTIC B CELLS INDICATING DISRUPTION OF APOPTOSIS. RESTRICTION LANDMARK GENOME SCANNING WAS DONE TO IDENTIFY NOVEL TARGET GENES SILENCED BY CPG ISLAND METHYLATION IN CLL. SECRETED FRIZZLED-RELATED PROTEIN 4 (SFRP4), A NEGATIVE REGULATOR OF THE WNT SIGNALING PATHWAY, WAS FOUND TO BE FREQUENTLY METHYLATED IN CLL SAMPLES. WNT SIGNALING HAS BEEN SHOWN TO CONTROL NORMAL APOPTOTIC BEHAVIOR AND IS REQUIRED FOR NORMAL B-CELL DEVELOPMENT WHEREAS ABERRANT ACTIVATION OF THIS PATHWAY HAS BEEN OBSERVED IN CLL. WE SHOW ABERRANT DNA METHYLATION AND SILENCING OF SFRP4, AS WELL AS OF ADDITIONAL SFRP FAMILY MEMBERS, IN PRIMARY CLL SAMPLES. INDUCTION OF THEIR EXPRESSION IN A DOSE-DEPENDENT MANNER FOLLOWING TREATMENT WITH A DEMETHYLATING AGENT, 5-AZA-2'-DEOXYCYTIDINE, WAS SHOWN. OF THE FIVE SFRP FAMILY MEMBERS STUDIED IN DETAIL, SFRP1 WAS HYPERMETHYLATED AND DOWN-REGULATED IN ALL CLL PATIENT SAMPLES STUDIED, SUGGESTING THAT THIS EPIGENETIC EVENT IS A CRITICAL STEP DURING LEUKEMOGENESIS. OUR RESULTS SUGGEST THAT SILENCING OF SFRPS BY CPG ISLAND METHYLATION IS ONE POSSIBLE MECHANISM CONTRIBUTING TO ABERRANT ACTIVATION OF WNT SIGNALING PATHWAY IN CLL. 2006 4 2435 42 EPIGENETIC SILENCING OF SFRP1 ACTIVATES THE CANONICAL WNT PATHWAY AND CONTRIBUTES TO INCREASED CELL GROWTH AND PROLIFERATION IN HEPATOCELLULAR CARCINOMA. THE WNT PATHWAY IS A KEY REGULATOR OF EMBRYONIC DEVELOPMENT AND STEM CELLS, AND ITS ABERRANT ACTIVATION IS ASSOCIATED WITH HUMAN MALIGNANCIES, MOST NOTABLY HEPATOCELLULAR CARCINOMA (HCC). EPIGENETIC DEREGULATION OF THE GENES ENCODING THE SECRETED FRIZZLED-RELATED PROTEINS (SFRPS), THE WNT SIGNALLING ANTAGONISTS, HAS BEEN LINKED WITH ABERRANT HYPERACTIVATION OF THE WNT SIGNALLING IN HCC CELLS; HOWEVER, THE PRECISE UNDERLYING MECHANISM REMAINS ELUSIVE. WE INVESTIGATED THE METHYLATION PROFILES OF WNT ANTAGONISTS IN LIVER SAMPLES OF DIFFERENT STAGES OF HCC DEVELOPMENT AND LIVER CANCER CELL LINES AND STUDIED THE FUNCTIONAL IMPACT OF ABERRANT EPIGENETIC SILENCING OF SFRPS ON THE CANONICAL WNT PATHWAY AND CELL VIABILITY. WE FOUND THAT THE SFRP1 GENE ENCODING THE SUBUNIT IS A FREQUENT TARGET OF ABERRANT DNA HYPERMETHYLATION AND SILENCING IN HCC TUMOURS, WHEREAS OTHER EXTRACELLULAR WNT ANTAGONISTS, WIF1 AND DKK3, EXHIBITED NO METHYLATION IN TUMOUR CELLS, CONSISTENT WITH THE NOTION THAT ABERRANT METHYLATION EVENTS IN CANCER CELLS ARE NON-RANDOMLY DISTRIBUTED AMONG THE GENES AND THAT THERE IS A STRONG PREFERENCE FOR HYPERMETHYLATION OF SPECIFIC GENES IN HCC. IN ADDITION, BY COMPARING SFRP1 METHYLATION STATUS IN HCC TUMOURS WITH NORMAL, CIRRHOTIC AND CHRONIC HEPATITIS LIVER TISSUES, WE IDENTIFIED SFRP1 GENE AS A POTENTIAL EARLY MARKER OF HCC. THE RESTORATION OF SFRP1 EXPRESSION IN CANCER CELLS BY ECTOPIC EXPRESSION INHIBITED WNT ACTIVITY ACCOMPANIED WITH DESTABILIZATION OF BETA-CATENIN AND DOWNREGULATION OF C-MYC AND CYCLIN D1, THE KNOWN DOWNSTREAM TARGETS OF WNT PATHWAY. IMPORTANTLY, RESTORING SFRP1 LEVELS IN CANCER CELLS INHIBITED CELL GROWTH AND INDUCED APOPTOTIC CELL DEATH. THIS STUDY SUPPORTS THE CRITICAL ROLE FOR SFRP1 SILENCING IN HEPATOCELLULAR CARCINOMA AND REINFORCES THE IMPORTANCE OF THE WNT ANTAGONISTS IN PREVENTING ONCOGENIC STABILIZATION OF BETA-CATENIN AND CHRONIC ACTIVATION OF THE CANONICAL WNT PATHWAY, SUGGESTING THAT SFRP1 MAY BE AN ATTRACTIVE TARGET FOR EARLY CANCER DETECTION AND THERAPEUTIC INTERVENTION. 2012 5 5669 30 SFRP1 PROMOTER METHYLATION IS ASSOCIATED WITH PERSISTENT PHILADELPHIA CHROMOSOME IN CHRONIC MYELOID LEUKEMIA. EPIGENETIC SILENCING OF SFRP GENES HAS BEEN SHOWN TO LEAD TO CONSTITUTIVE ACTIVATION OF THE CANONICAL WNT-SIGNALING PATHWAY. THE FIRST DESCRIPTION OF DEREGULATED WNT-SIGNALING ACTIVATION IN A HEMATOLOGICAL MALIGNANCY WAS REPORTED IN CHRONIC MYELOID LEUKEMIA (CML). TO INVESTIGATE WHETHER EPIGENETIC SILENCING OF SFRP IS RESPONSIBLE FOR THE OBSERVED WNT ACTIVATION IN CML, WE STUDIED THE METHYLATION AND MUTATIONAL STATUS OF THE SFRP1 PROMOTER IN 48 CHRONIC PHASE CML PATIENTS. OF THE 48 CML PATIENTS 41 WERE SHOWN TO BE UNMETHYLATED, 6 PATIENTS HEMI-METHYLATED AND 1 PATIENT FULLY METHYLATED AT THE SFRP1 PROMOTER. ALBEIT OBSERVED INFREQUENTLY IN CHRONIC PHASE CML, SFRP1 PROMOTER METHYLATION CORRELATED WITH PRIMARY CYTOGENETIC RESISTANCE TO IMATINIB MESYLATE. SFRP1 PROMOTER METHYLATION MAY INDICATE A GENETICALLY MORE UNSTABLE FORM OF DISEASE RESISTANT TO THERAPY AND PROVIDE A KEY BIOLOGICAL DIFFERENCE IN THERAPY RESISTANT PATIENTS, IN ADDITION TO A POSSIBLE MECHANISM FOR THE OBSERVED ACTIVATION OF CANONICAL WNT SIGNALING IN CML. 2009 6 5668 35 SFRP1 EXPRESSION REGULATES WNT SIGNALING IN CHRONIC MYELOID LEUKEMIA K562 CELLS. BACKGROUND: WNT SIGNALING CASCADES PLAY IMPORTANT ROLES IN CELL FATE DECISIONS AND THEIR DEREGULATION HAS BEEN DOCUMENTED IN MANY DISEASES, INCLUDING MALIGNANT TUMORS AND LEUKEMIA. ONE MECHANISM OF ABERRANT WNT SIGNALING IS THE SILENCING OF WNT INHIBITORS THROUGH EPIGENETIC MECHANISMS. THE SFRPS ARE ONE OF THE MOST STUDIED WNT INHIBITORS; AND THE SFRP1 LOSS IS KNOWN IN MANY HEMATOLOGICAL MALIGNANCIES. THEREFORE, WE AIMED TO COMPARE THE EXPRESSION OF WNT RELATED GENES IN THE PRESENCE AND ABSENCE OF SFRP1 IN A CHRONIC MYELOID LEUKEMIA (CML) CELL LINE. OBJECTIVE: IT IS IMPORTANT TO UNDERSTAND HOW SFRP1 AND SFRP1 PERFORM THEIR EFFECTS ON CML TO DESIGN NEW AGENTS AND STRATEGIES FOR RESISTANT AND ADVANCED FORMS OF CML. MATERIALS AND METHODS: WE USED K562 CELLS, WHICH NORMALLY DO NOT EXPRESS SFRP1 AND ITS SFRP1 EXPRESSING SUBCLONE K562S. TOTAL RNA WAS ISOLATED FROM K562 AND K562S CELL LINES AND CONVERTED TO CDNA. PCR ARRAY EXPERIMENTS WERE PERFORMED USING HUMAN WNT SIGNALING PATHWAY PLUS RT2 PROFILER KIT. WNT SIGNALING PATHWAY ACTIVATION WAS STUDIED BY WESTERN BLOT FOR DOWNSTREAM SIGNALING TARGETS. RESULTS: THE WNT3, LRP6, PRICKLE1 AND BTRC EXPRESSIONS WERE SIGNIFICANTLY DECREASED IN THE PRESENCE OF SFRP1; WHILE WNT5B INCREASED. THE SFRP1 EXPRESSION INHIBITED STABILIZATION OF TOTAL BETA-CATENIN PROTEIN AND DOWNSTREAM EFFECTOR PHOSPHORYLATION OF NONCANONICAL WNT/PCP SIGNALING; WHEREAS CA2+/PKC SIGNALING REMAINED ACTIVE. CONCLUSION: THE RESULTS SUGGEST THAT SFRP1 COULD BE A PROMISING THERAPEUTIC ANTICANCER AGENT. DEFINING THESE PATHWAY INTERACTIONS IS CRUCIAL FOR DESIGNING NEW AGENTS RESISTANT AND ADVANCED FORMS OF CML. 2022 7 4201 33 METABOLIC REWIRING AND REDOX ALTERATIONS IN MALIGNANT PLEURAL MESOTHELIOMA. MALIGNANT PLEURAL MESOTHELIOMA (MPM) IS A RARE MALIGNANCY OF MESOTHELIAL CELLS WITH INCREASING INCIDENCE, AND IN MANY CASES, DISMAL PROGNOSIS DUE TO ITS AGGRESSIVENESS AND LACK OF EFFECTIVE THERAPIES. ENVIRONMENTAL AND OCCUPATIONAL EXPOSURE TO ASBESTOS IS CONSIDERED THE MAIN AETIOLOGICAL FACTOR FOR MPM. INHALED ASBESTOS FIBRES ACCUMULATE IN THE LUNGS AND INDUCE THE GENERATION OF REACTIVE OXYGEN SPECIES (ROS) DUE TO THE PRESENCE OF IRON ASSOCIATED WITH THE FIBROUS SILICATES AND TO THE ACTIVATION OF MACROPHAGES AND INFLAMMATION. CHRONIC INFLAMMATION AND A ROS-ENRICHED MICROENVIRONMENT CAN FOSTER THE MALIGNANT TRANSFORMATION OF MESOTHELIAL CELLS. IN ADDITION, MPM CELLS HAVE A HIGHLY GLYCOLYTIC METABOLIC PROFILE AND ARE POSITIVE IN (18)F-FDG PET ANALYSIS. LOSS-OF-FUNCTION MUTATIONS OF BRCA-ASSOCIATED PROTEIN 1 (BAP1) ARE A MAJOR CONTRIBUTOR TO THE METABOLIC REWIRING OF MPM CELLS. A SUBSET OF MPM TUMOURS SHOW LOSS OF THE METHYLADENOSINE PHOSPHORYLASE (MTAP) LOCUS, RESULTING IN PROFOUND ALTERATIONS IN POLYAMINE METABOLISM, ATP AND METHIONINE SALVAGE PATHWAYS, AS WELL AS CHANGES IN EPIGENETIC CONTROL OF GENE EXPRESSION. THIS REVIEW PROVIDES AN OVERVIEW OF THE PERTURBATIONS IN METABOLISM AND ROS HOMOEOSTASIS OF MPM CELLS AND THE ROLE OF THESE ALTERATIONS IN MALIGNANT TRANSFORMATION AND TUMOUR PROGRESSION. 2020 8 1065 32 CLINICAL SIGNIFICANCE OF SERUM DRAM1 MRNA, ARSA MRNA, HSA-MIR-2053 AND LNCRNA-RP1-86D1.3 AXIS EXPRESSION IN MALIGNANT PLEURAL MESOTHELIOMA. AIM AND BACKGROUND: MALIGNANT PLEURAL MESOTHELIOMA (MPM) IS A LETHAL CANCER MAINLY CAUSED BY CHRONIC EXPOSURE OF ASBESTOS. IN THIS PILOT STUDY, WE AIMED TO ASSESS THE EXPRESSION OF SERUM RNA-BASED BIOMARKER PANEL EXPLORING THEIR CLINICAL UTILITY AS DIAGNOSTIC AND PROGNOSTIC BIOMARKERS FOR MPM. METHODS: WE HAVE SELECTED AN MPM-SPECIFIC RNA-BASED BIOMARKER PANEL THROUGH BIOINFORMATICS ANALYSIS BASED ON THE INTEGRATION OF DNA DAMAGE REGULATED AUTOPHAGY MODULATOR 1 (DRAM1) AND ARYLSULFATASE A ( ARSA) GENE EXPRESSION WITH THEIR EPIGENETIC REGULATORS MICRORNA ( MIR-2053) AND LONG NONCODING RNA ( LNCRNA-RP1-86D1.3). THEN, QUANTITATIVE REAL-TIME POLYMERASE CHAIN REACTION (QPCR) VALIDATION IN SERA OF 60 MPM PATIENTS, 20 CHRONIC ASBESTOS EXPOSURE PATIENTS, AND 20 HEALTHY VOLUNTEERS WAS DONE. LASTLY, THE PROGNOSTIC POWER OF THE SELECTED PANEL WAS ASSESSED. RESULTS: THE EXPRESSION OF SERUM DRAM1 MESSENGER RNA (MRNA), ARSA MRNA, HSA-MIR-2053 AND LNCRNA-RP1-86D1.3 WERE POSITIVE IN 78.3%, 90%, 85%, AND 83.3% OF MPM PATIENTS, RESPECTIVELY. THE RNA-BASED BIOMARKER PANEL WAS ABLE TO DISCRIMINATE BETWEEN MPM PATIENTS AND CONTROLS WITH HIGH ACCURACY AND THEIR COMBINED SENSITIVITY REACHED 100% FOR THE DIAGNOSIS OF MPM. KAPLAN-MEIER ANALYSIS SHOWED THAT HSA-MIR-2053 IS AN INDEPENDENT PROGNOSTIC FACTOR OF MPM. CONCLUSION: OUR PRELIMINARY DATA REVEALED THAT THE CHOSEN RNAS PLAY AN IMPORTANT ROLE IN DRIVING MPM DEVELOPMENT AND PROGRESSION. 2019 9 1146 48 CONCURRENT EPIGENETIC SILENCING OF WNT/BETA-CATENIN PATHWAY INHIBITOR GENES IN B CELL CHRONIC LYMPHOCYTIC LEUKAEMIA. BACKGROUND: THE WNT/BETA-CATENIN SIGNALLING IS ABERRANTLY ACTIVATED IN PRIMARY B CELL CHRONIC LYMPHOCYTIC LEUKAEMIA (CLL). EPIGENETIC SILENCING OF PATHWAY INHIBITOR GENES MAY BE A MECHANISM FOR ITS ACTIVATION. IN THIS STUDY, WE INVESTIGATED SYSTEMATICALLY AND QUANTITATIVELY THE METHYLATION STATUS OF 12 WNT/BETA-CATENIN PATHWAY INHIBITOR GENES - CDH1, DACT1, DKK1, DKK2, DKK3, DKK4, SFRP1, SFRP2, SFRP3, SFRP4, SFRP5 AND WIF1 - IN THE CELL LINES EHEB AND MEC-1 AS WELL AS PATIENT SAMPLES. METHODS: QUANTIFICATION OF DNA METHYLATION WAS PERFORMED BY MEANS OF BISULPHITE PYROSEQUENCING AND CONFIRMED BY BISULPHITE SANGER SEQUENCING. GENE EXPRESSION WAS ANALYSED BY QPCR USING GAPDH AS INTERNAL CONTROL. E-CADHERIN AND BETA-CATENIN PROTEIN QUANTIFICATION WAS CARRIED OUT BY MICROSPHERE-BASED IMMUNOASSAYS. METHYLATION DIFFERENCES OBSERVED BETWEEN THE PATIENT AND CONTROL GROUPS WERE TESTED USING GENERALISED LEAST SQUARES MODELS. RESULTS: FOR 10 GENES, A HIGHER METHYLATION LEVEL WAS OBSERVED IN TUMOUR MATERIAL. ONLY DKK4 EXHIBITED SIMILARLY HIGH METHYLATION LEVELS IN BOTH TUMOUR AND NORMAL SPECIMENS, WHILE DACT1 WAS ALWAYS ESSENTIALLY UNMETHYLATED. HOWEVER, ALSO FOR THESE INHIBITORS, TREATMENT OF CELLS WITH THE DEMETHYLATING AGENT 5-AZA-2 -DEOXYCYTIDINE RESULTED IN AN INDUCTION OF THEIR EXPRESSION, AS SHOWN BY QUANTITATIVE PCR, SUGGESTING AN INDIRECT EPIGENETIC CONTROL OF ACTIVITY. WHILE THE DEGREE OF DEMETHYLATION AND ITS TRANSCRIPTIONAL CONSEQUENCES DIFFERED BETWEEN THE GENES, THERE WAS AN OVERALL HIGH CORRELATION OF DEMETHYLATION AND INCREASED ACTIVITY. PROTEIN EXPRESSION STUDIES REVEALED THAT NO CONSTITUTIVE WNT/BETA-CATENIN SIGNALLING OCCURRED IN THE CELL LINES, WHICH IS IN DISCREPANCY WITH RESULTS FROM PRIMARY CLL. HOWEVER, TREATMENT WITH 5-AZA-2 -DEOXYCYTIDINE CAUSED ACCUMULATION OF BETA-CATENIN. SIMULTANEOUSLY, E-CADHERIN EXPRESSION WAS STRONGLY INDUCED, LEADING TO THE FORMATION OF A COMPLEX WITH BETA-CATENIN AND THUS DEMONSTRATING ITS EPIGENETICALLY REGULATED INHIBITION EFFECT. CONCLUSIONS: THE RESULTS SUGGEST AN EPIGENETIC SILENCING MECHANISM OF THE WNT/BETA-CATENIN PATHWAY INHIBITOR GENES IN CLL. HYPERMETHYLATION AND SILENCING OF FUNCTIONALLY RELATED GENES MAY NOT BE COMPLETELY STOCHASTIC BUT RESULT FROM THE TUMOUR EPIGENOME REPROGRAMMING ORCHESTRATED BY POLYCOMB-GROUP REPRESSIVE COMPLEXES. THE DATA ARE OF INTEREST IN THE CONTEXT OF EPIGENETIC-BASED THERAPY. 2012 10 3444 30 HYPERMETHYLATION OF E-CADHERIN IN LEUKEMIA. E-CADHERIN GENE IS OFTEN TERMED A "METASTASIS SUPPRESSOR" GENE BECAUSE THE E-CADHERIN PROTEIN CAN SUPPRESS TUMOR CELL INVASION AND METASTASIS. INACTIVATION OF THE E-CADHERIN GENE OCCURS IN UNDIFFERENTIATED SOLID TUMORS BY BOTH GENETIC AND EPIGENETIC MECHANISMS; HOWEVER, THE ROLE OF E-CADHERIN IN HEMATOLOGIC MALIGNANCIES IS ONLY NOW BEING RECOGNIZED. E-CADHERIN EXPRESSION IS ESSENTIAL FOR ERYTHROBLAST AND NORMOBLAST MATURATION, YET EXPRESSION IS REDUCED OR ABSENT IN LEUKEMIC BLAST CELLS. THIS STUDY EXAMINED THE MESSENGER RNA (MRNA) AND PROTEIN EXPRESSION OF THE E-CADHERIN GENE IN BONE MARROW AND BLOOD SAMPLES FROM NORMAL DONORS AND PATIENTS WITH LEUKEMIA. WE FOUND THAT ALL NORMAL DONOR SAMPLES EXPRESSED E-CADHERIN MRNA, WHEREAS BOTH SAMPLES OF ACUTE MYELOGENOUS LEUKEMIA AND CHRONIC LYMPHOCYTIC LEUKEMIA HAD A SIGNIFICANT REDUCTION OR ABSENCE OF EXPRESSION. HOWEVER, NORMAL BLAST COUNTERPARTS EXPRESSED ONLY A LOW LEVEL OF E-CADHERIN SURFACE PROTEIN. SODIUM BISULPHITE GENOMIC SEQUENCING WAS USED TO FULLY CHARACTERIZE THE METHYLATION PATTERNS OF THE CPG ISLAND ASSOCIATED WITH THE E-CADHERIN GENE PROMOTER IN THOSE SAMPLES WITH MATCHED DNA. ALL OF THE NORMAL CONTROL SAMPLES WERE ESSENTIALLY UNMETHYLATED; HOWEVER, 14 OF 18 (78%) OF THE LEUKEMIA SAMPLES HAD ABNORMAL HYPERMETHYLATION OF THE E-CADHERIN CPG ISLAND. IN FACT BOTH ALLELES OF THE E-CADHERIN GENE WERE OFTEN HYPERMETHYLATED. WE CONCLUDE THE E-CADHERIN GENE IS A COMMON TARGET FOR HYPERMETHYLATION IN HEMATOLOGIC MALIGNANCIES. 2000 11 2379 31 EPIGENETIC REGULATION OF WNT PATHWAY ANTAGONISTS IN HUMAN GLIOBLASTOMA MULTIFORME. EPIGENETIC INACTIVATION OF TUMOR SUPPRESSOR GENES IS COMMON IN HUMAN CANCER. USING A LARGE-SCALE WHOLE-GENOME APPROACH IN AN EARLIER STUDY, THE AUTHORS IDENTIFIED EPIGENETICALLY SILENCED GENES WITH POTENTIAL TUMOR SUPPRESSOR FUNCTION IN GLIOBLASTOMA (GBM). THREE GENES IDENTIFIED IN THIS ANALYSIS-DKK1, SFRP1, AND WIF1-ARE POTENT INHIBITORS OF THE WNT SIGNAL TRANSDUCTION PATHWAY. HERE, THE AUTHORS CONFIRM DECREASED EXPRESSION OF THESE GENES IN GBM TUMOR TISSUE SAMPLES RELATIVE TO NONTUMOR BRAIN TISSUE SAMPLES USING REAL-TIME PCR. THEY THEN SHOW THAT EXPRESSION OF ALL 3 GENES IS RESTORED IN T98 GBM CELLS BY TREATMENT WITH THE HISTONE DEACETYLASE INHIBITOR TRICHOSTATIN A (TSA), BUT ONLY DKK1 EXPRESSION IS RESTORED BY TREATMENT WITH THE DEMETHYLATING AGENT 5-AZACYTIDINE. BISULFITE SEQUENCING DID NOT REVEAL SIGNIFICANT METHYLATION IN THE PROMOTER REGION OF DKK1, WHEREAS HISTONE ACETYLATION AND CHROMATIN ACCESSIBILITY INCREASED SIGNIFICANTLY FOR ALL 3 GENES AFTER TSA TREATMENT. ECTOPIC EXPRESSION OF DKK1 SIGNIFICANTLY REDUCES COLONY FORMATION AND INCREASES CHEMOTHERAPY-INDUCED APOPTOSIS IN T98 CELLS. ECTOPIC EXPRESSION OF THE CANONICAL WNT PATHWAY INHIBITORS WIF1 AND SFRP1 SHOWS A RELATIVE LACK OF RESPONSE. CHRONIC WNT3A STIMULATION ONLY PARTIALLY REVERSES GROWTH SUPPRESSION AFTER DKK1 REEXPRESSION, WHEREAS A SPECIFIC INHIBITOR OF THE JNK PATHWAY SIGNIFICANTLY REVERSES THE EFFECT OF DKK1 REEXPRESSION ON COLONY FORMATION AND APOPTOSIS IN T98 CELLS. THESE RESULTS SUPPORT A POTENTIAL GROWTH-SUPPRESSIVE FUNCTION FOR EPIGENETICALLY SILENCED DKK1 IN GBM AND SUGGEST THAT DKK1 RESTORATION COULD MODULATE WNT SIGNALING THROUGH BOTH CANONICAL AND NONCANONICAL PATHWAYS. 2010 12 59 32 A GENOME-WIDE SCREEN IDENTIFIES FREQUENTLY METHYLATED GENES IN HAEMATOLOGICAL AND EPITHELIAL CANCERS. BACKGROUND: GENETIC AS WELL AS EPIGENETIC ALTERATIONS ARE A HALLMARK OF BOTH EPITHELIAL AND HAEMATOLOGICAL MALIGNANCIES. HIGH THROUGHPUT SCREENS ARE REQUIRED TO IDENTIFY EPIGENETIC MARKERS THAT CAN BE USEFUL FOR DIAGNOSTIC AND PROGNOSTIC PURPOSES ACROSS MALIGNANCIES. RESULTS: HERE WE REPORT FOR THE FIRST TIME THE USE OF THE MIRA ASSAY (METHYLATED CPG ISLAND RECOVERY ASSAY) IN COMBINATION WITH GENOME-WIDE CPG ISLAND ARRAYS TO IDENTIFY EPIGENETIC MOLECULAR MARKERS IN CHILDHOOD ACUTE LYMPHOBLASTIC LEUKEMIA (ALL) ON A GENOME-WIDE SCALE. WE IDENTIFIED 30 GENES DEMONSTRATING METHYLATION FREQUENCIES OF > OR =25% IN CHILDHOOD ALL, NINE GENES SHOWED SIGNIFICANTLY DIFFERENT METHYLATION FREQUENCIES IN B VS T-ALL. FOR MAJORITY OF THE GENES EXPRESSION COULD BE RESTORED IN METHYLATED LEUKEMIA LINES AFTER TREATMENT WITH 5-AZADC. FORTY-FOUR PERCENT OF THE GENES REPRESENT TARGETS OF THE POLYCOMB COMPLEX. IN CHRONIC MYELOID LEUKEMIA (CML) TWO OF THE GENES, (TFAP2A AND EBF2), DEMONSTRATED INCREASED METHYLATION IN BLAST CRISIS COMPARED TO CHRONIC PHASE (P < 0.05). FURTHERMORE HYPERMETHYLATION OF AN AUTOPHAGY RELATED GENE ATG16L2 WAS ASSOCIATED WITH POORER PROGNOSIS IN TERMS OF MOLECULAR RESPONSE TO IMATINIB TREATMENT. LASTLY WE DEMONSTRATED THAT TEN OF THESE GENES WERE ALSO FREQUENTLY METHYLATED IN COMMON EPITHELIAL CANCERS. CONCLUSION: IN SUMMARY WE HAVE IDENTIFIED A LARGE NUMBER OF GENES SHOWING FREQUENT METHYLATION IN CHILDHOOD ALL, METHYLATION STATUS OF TWO OF THESE GENES IS ASSOCIATED WITH ADVANCED DISEASE IN CML AND METHYLATION STATUS OF ANOTHER GENE IS ASSOCIATED WITH PROGNOSIS. IN ADDITION A SUBSET OF THESE GENES MAY ACT AS EPIGENETIC MARKERS ACROSS HEMATOLOGICAL MALIGNANCIES AS WELL AS COMMON EPITHELIAL CANCERS. 2010 13 2071 31 EPIGENETIC CONTROL OF THE E-CADHERIN GENE (CDH1) BY CPG METHYLATION IN COLECTOMY SAMPLES OF PATIENTS WITH ULCERATIVE COLITIS. E-CADHERIN BELONGS TO THE CADHERIN FAMILY OF CALCIUM-DEPENDENT CELL-ADHESION MOLECULES. THE CADHERINS PLAY AN ESSENTIAL ROLE IN BIOLOGICAL PROCESSES SUCH AS ORDERING OF CELL SORTING, MIGRATION, AND DIFFERENTIATION, AND THEIR MALFUNCTIONING IS CONNECTED WITH NEOPLASIA. NEOPLASTIC PROGRESSION IN PATIENTS WITH CHRONIC ULCERATIVE COLITIS IS CHARACTERIZED BY THE DEVELOPMENT OF EPITHELIAL DYSPLASIA. TRANSCRIPTIONAL SILENCING OF TUMOR-SUPPRESSOR GENES BY PROMOTER METHYLATION HAS BEEN OBSERVED IN DIFFERENT TYPES OF HUMAN CANCERS AND DYSPLASIA. TO EXPLORE THE MODE OF E-CADHERIN REGULATION, 156 BIOPSY SAMPLES FROM 26 PATIENTS WITH LONG-STANDING ULCERATIVE COLITIS WERE SCREENED. TO DETECT THE METHYLATION STATUS OF OUR SAMPLES, A METHYLATION-SPECIFIC PCR WAS APPLIED. METHYLATION OF THE E-CADHERIN (CDH1) PROMOTER WAS DETECTED IN 93% OF THE PATIENTS WITH DYSPLASTIC BIOPSY SAMPLES, IN CONTRAST TO ONLY 6% OF THE PATIENTS WITHOUT DYSPLASIA (P < 0.001). WE ALSO EXAMINED THE LEVEL OF SYNTHESIS OF E-CADHERIN PROTEIN BY IMMUNOHISTOCHEMICAL STAINING IN DIFFERENT PARAFFIN-EMBEDDED SAMPLES OF DYSPLASTIC AND NON-DYSPLASTIC ORIGIN IN A SUBSET OF OUR PATIENTS. SAMPLES WITH DYSPLASIA DISPLAYED REDUCED LEVELS, WHEREAS SAMPLES WITHOUT DYSPLASIA REVEALED NORMAL E-CADHERIN PROTEIN SYNTHESIS. THESE RESULTS SHOW THAT THE E-CADHERIN PROMOTER IS SUBJECTED TO EPIGENETIC CONTROL IN COLORECTAL ULCERATION. OBVIOUSLY, THIS EVENT MAY PLAY AN IMPORTANT ROLE IN THE PROGRESSION FROM CHRONIC INFLAMMATION TO COLORECTAL CANCER. FOR THIS REASON, METHYLATION OF THE CDH1 PROMOTER IS AN ATTRACTIVE NEW BIOMARKER FOR DETECTING ULCERATIVE COLITIS PATIENTS WITH A HIGH RISK FOR DEVELOPING COLORECTAL CANCERS. 2002 14 5458 31 RESEARCH ON EPIGENETIC MECHANISM OF SFRP2 IN ADVANCED CHRONIC MYELOID LEUKEMIA. SECRETED FRIZZLED-RELATED PROTEIN 2 (SFRP2) HAS BEEN REPORTED TO ACT AS A TUMOR SUPPRESSORS. THIS STUDY AIMS TO DETECT THE BIOLOGICAL ROLE OF SFRP2 IN ADVANCED CHRONIC MYELOID LEUKEMIA (CML). IN THIS STUDY WE EXAMINED BONE MARROW SAMPLES FROM 45 CML PATIENTS AND 10 HEALTHY DONORS. K562 AND KCL22 CELLS WERE CULTURED AND TREATED WITH DEMETHYLATION DRUG AND HISTONE DEACETYLASE INHIBITOR (HDACI). KCL22 AND K562 CELLS WERE TRANSFECTED WITH LENTIVIRAL VECTOR (LV)-SFRP2, LV-CONTROL. THE CELLS WERE THEN SUBJECTED TO PROLIFERATION AND APOPTOSIS ASSAYS, REAL TIME POLYMERASE CHAIN REACTION (PCR), METHYLATION-SPECIFIC PCR (MSP), WESTERN BLOTTING, CO-IMMUNOPRECIPITATION (COIP) AND CHROMATIN IMMUNOPRECIPITATION (CHIP), WE FOUND THAT SFRP2 WAS DOWN-REGULATED IN THE ACCELERATED AND BLAST PHASE OF CML, WHEREAS, THE LEVELS OF WNT1, WNT3 AND WNT5A WERE UP-REGULATED IN THE ACCELERATED AND BLAST PHASE OF CML. OVEREXPRESSION SFRP2 INHIBITED PROLIFERATION, PROMOTED APOPTOSIS AND ACTIVATED THE WNT PATHWAY. COIP-MS RESULTS SHOWED THAT SFRP2 INTERACTED WITH WNT1 AND WNT5A. CHIP-SEQ RESULT INDICATED THAT THE PROMOTER OF H3K4ME3 AND H3K27ME3 WERE ABLE TO INTERACT WITH SFRP2. IN CONCLUSION, OUR FINDINGS DEMONSTRATED THE SFRP2 ACT AS A POTENTIAL THERAPEUTIC TARGET FOR ADVANCED CML. FURTHERMORE, OUR RESULTS SUPPORT THE USE OF DEMETHYLATION DRUGS AND HDACI AS A POTENTIAL CML TREATMENT STRATEGY. 2018 15 3896 38 LARGE-SCALE ANALYSIS OF DNA METHYLATION IN CHRONIC LYMPHOCYTIC LEUKEMIA. AIMS: B-CELL CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) IS A HETEROGENEOUS MALIGNANCY THAT CLINICALLY RANGES FROM INDOLENT TO RAPIDLY PROGRESSIVE. CLL, LIKE OTHER CANCERS, CAN BE AFFECTED BY EPIGENETIC ALTERATIONS. MATERIALS & METHODS: A MICROARRAY DISCOVERY-BASED STUDY WAS INITIATED TO DETERMINE DNA METHYLATION IN CLL CASES WITH A RANGE OF CD38 EXPRESSION (1-92%). RESULTS: MANY LOCI WERE EITHER METHYLATED OR UNMETHYLATED ACROSS ALL CD38 LEVELS, BUT DIFFERENTIAL METHYLATION WAS ALSO OBSERVED FOR SOME GENES. GENOMIC SEQUENCING OF DLEU7 CONFIRMED EXTENSIVE CYTOSINE METHYLATION PREFERENTIALLY IN PATIENT SAMPLES WITH LOW CD38 EXPRESSION, WHEREAS NRP2, SFRP2 AND ADAM12 WERE MORE COMMONLY METHYLATED IN THOSE WITH HIGH CD38 EXPRESSION. CONCLUSION: THIS STUDY DEMONSTRATES THAT CLL IS AFFECTED BY CPG ISLAND METHYLATION IN SOME GENES THAT SEGREGATE WITH CD38 EXPRESSION LEVELS, WHILE MOST OTHERS SHOW SIMILAR METHYLATION PATTERNS ACROSS ALL LEVELS. THE CPG ISLAND METHYLATION IN CERTAIN FUNCTIONAL GENE GROUPS AND PATHWAY-ASSOCIATED GENES THAT ARE KNOWN TO BE DEREGULATED IN CLL PROVIDES ADDITIONAL INSIGHTS INTO THE CLL METHYLOME AND EPIGENETIC CONTRIBUTION TO CELLULAR DYSFUNCTION. IT WILL NOW BE USEFUL TO INVESTIGATE THE EFFECTIVENESS OF EPIGENETIC THERAPEUTIC REVERSAL OF THESE ALTERATIONS TO DEVELOP EFFECTIVE TREATMENTS FOR THE DISEASE. 2009 16 1968 30 EPIGENETIC ALTERATION OF THE SOCS1 GENE IN CHRONIC MYELOID LEUKAEMIA. THE EXPRESSION OF THE SUPPRESSOR OF CYTOKINE SIGNALLING-1 (SOCS1) PROTEIN IS INDUCED IN RESPONSE TO STIMULATION BY SEVERAL CYTOKINES. THE INDUCED SOCS1 INHIBITS THE SIGNALLING PATHWAY THROUGH THE ASSOCIATION WITH A VARIETY OF TYROSINE KINASE PROTEINS. IN THIS STUDY, THE MUTATION ANALYSES, CPG ISLAND METHYLATION STATUS, AND THE EXPRESSION OF THE SOCS1 GENE IN 112 CHRONIC MYELOID LEUKAEMIA (CML) SAMPLES, FIVE LEUKAEMIA CELL LINES, AND 30 NORMAL CONTROLS WERE ANALYSED. NO GENETIC MUTATIONS OF SOCS1 GENE WERE NOTED IN THE CML SAMPLES. THE SOCS1 GENE WAS HYPERMETHYLATED IN 67% AND 46% OF THE BLASTIC AND CHRONIC PHASE CML SAMPLES RESPECTIVELY (P < 0.0001). HOWEVER, THERE WAS NO METHYLATION OF THE SOCS1 GENE IN NORMAL CONTROLS OR CML IN MOLECULAR REMISSION. THE METHYLATION STATUS OF THE SOCS1 GENE IS CONSISTENT WITH THE RESULTS OF THE REAL-TIME QUANTITATIVE REVERSE TRANSCRIPTION POLYMERASE CHAIN REACTION AND IMMUNOCYTOCHEMISTRY STAINING. OUR RESULTS DEMONSTRATE THAT THE SOCS1 GENE SILENCING IS CAUSED BY THE METHYLATION OF CPG ISLANDS IN CML AND IS REVERSED TO AN UNMETHYLATED STATUS IN MOLECULAR REMISSION. AS SOCS1 HAS UNIVERSAL ACTIVITY TO NEGATIVELY REGULATE SEVERAL CYTOKINE SIGNALLING PATHWAYS, THE LOSS OF THE NEGATIVE REGULATION OF CYTOKINE SIGNALLING BY THE SOCS1 MAY PLAY A ROLE IN THE PATHOGENESIS OF CML PROGRESSION. 2003 17 6820 37 [GASTRIC CARCINOMA AND CHRONIC GASTRITIS: EPIGENETIC REGULATION OF CDH1 (E-CADHERIN), CDKN2A (P16INK4A), PTGS2 (COX-2) AND EGFR GENES THROUGH METHYLATION]. THE GENETIC AND EPIGENETIC ALTERATIONS ARE BEING STUDIED AS ONE OF THE CAUSES OF GASTRIC CANCER (GC) PROGRESSION AND DEVELOPMENT. DNA METHYLATION IS AN EPIGENETIC ALTERATION WHICH LEADS TO SUPPRESSOR GENE SILENCING AND PROTO-ONCOGENE ACTIVATION, PLAYING AN IMPORTANT ROLE IN CARCINOGENESIS. THE HISTOLOGICAL TYPES OF GASTRIC CARCINOMA HAVE DIFFERENT GENETIC PATHS AND THE KNOWLEDGE OF THE MOLECULAR BASES OF TUMORAL PROGRESSION LEADS TO DIAGNOSTIC ACCURACY AND ATTEMPTED THERAPY. CDH1 (E-CADHERIN) AND CDKN2A (P16(INK4A)) GENES ARE THOUGHT TO BE TUMORAL SUPPRESSOR GENES AND PTGS2 (COX-2) AND GENES ARE INVOLVED IN TUMOUR REGULATION AND GROWTH. IN ONE HAND, GENE SILENCING AS AN EPIGENETIC PHENOMENON, AND IN THE OTHER HAND, GENE EXPRESSION ENHANCEMENT DUE TO POSSIBLE DEMETHYLATION, SIMULTANEOUSLY, CAN FACILITATE CARCINOGENESIS AND TUMORAL PROGRESSION. OUR AIM WAS TO RELATE CDH1, P16(INK4A), COX-2 AND EGFR GENES DNA METHYLATION WITH THE SEVERAL HISTOLOGICAL TYPES OF GASTRIC CARCINOMA AND CHRONIC GASTRITIS. WE STUDIED 55 FORMALIN FIXED PARAFFIN EMBEDDED GASTRIC BIOPSIES: 35 WERE GC SPECIMENS (12 DIFFUSE TYPE, 15 INTESTINAL TYPE AND 8 INDETERMINATE TYPE, ACCORDING TO LAUREN'S CLASSIFICATION) AND 20 SAMPLES HAD CHRONIC GASTRITIS (CG). THE DNA WAS TREATED WITH SODIUM BISULFITE AFTER EXTRACTION AND THEN PERFORMED METHYLATION SPECIFIC PCR (MSP). STATISTICAL ANALYSIS WAS BASED ON CHI-SQUARE TEST AND EXACT FISHER'S TEST. CPG ISLAND METHYLATION WAS DETECTED IN 94% OF THE GC SAMPLES FOR CDH1, 91% FOR COX-2, 80% FOR P16(INK4A) AND NO METHYLATION WAS DETECTED IN EGFR GENE (0%). IN CG, CPG ISLAND METHYLATION WAS FOUND IN 100% FOR CDH1 AND COX-2 GENES, 90% FOR P16(INK4A) AND 20% FOR EGFR. THESE RESULTS REVEAL SIGNIFICANT DIFFERENCES IN EGFR GENE METHYLATION DISTINGUISHING GC FROM CG (P < 0, 01), SUGGESTING THAT GENE DEMETHYLATION LEADS TO MALIGNANT TRANSFORMATION AND FAVOURS THE USE OF TYROSINE-KINASE INHIBITORS IN ITS TREATMENT. GENES COX2 E P16INK4A LOWER METHYLATION IN INTESTINAL AND DIFFUSE TYPES OF GC, FAVOURS THEIR DIFFERENT ROLE IN RESPECTIVE HISTOGENESIS. 2010 18 1805 28 EFFECT OF SMOKING ON THE DNA METHYLATION PATTERN OF THE SOCS1 PROMOTER IN EPITHELIAL CELLS FROM THE SALIVA OF PATIENTS WITH CHRONIC PERIODONTITIS. BACKGROUND: THE AIM OF THE PRESENT STUDY WAS TO EVALUATE THE METHYLATION PATTERN IN THE SUPPRESSOR OF CYTOKINE SIGNALING 1 (SOCS1) GENE IN SMOKERS AND NON-SMOKERS WITH CHRONIC PERIODONTITIS (CP). METHODS: METHYLATION-SPECIFIC POLYMERASE CHAIN REACTION (PCR) WAS PERFORMED TO DETERMINE THE METHYLATION STATUS OF THE SOCS1 PROMOTER IN 45 SALIVA SAMPLES FROM SMOKERS AND NON-SMOKERS WITH CP. RESULTS: CELLS FROM THE SALIVA OF CP PATIENTS WHO SMOKED WERE 7.08 TIMES MORE LIKELY TO HAVE A METHYLATED SOCS1 PROMOTER THAN CELLS FROM THE SALIVA OF NON-SMOKING PATIENTS. CONCLUSIONS: SOCS1 GENE PROMOTER METHYLATION, WITH ITS POTENTIAL EFFECTS ON THE EXPRESSION OF THIS GENE, SEEMS TO BE A CONSEQUENCE OF EXPOSURE TO TOBACCO AND NOT TO PERIODONTAL DISEASE. FURTHER STUDIES ARE NEEDED TO ELUCIDATE THE RELATIONSHIP BETWEEN THE EPIGENETIC CONTROL OF IMMUNE RESPONSE GENE EXPRESSION, EXPOSURE TO ENVIRONMENTAL FACTORS, AND THE DEVELOPMENT, PROGRESSION, AND PROGNOSIS OF CP. 2019 19 2380 26 EPIGENETIC REGULATION OF WNT SIGNALING IN CHRONIC LYMPHOCYTIC LEUKEMIA. CERTAIN WNT AND WNT NETWORK TARGET GENES ARE EXPRESSED AT HIGHER OR LOWER LEVELS IN CHRONIC LYMPHOCYTIC LEUKEMIA COMPARED WITH NORMAL B-CELLS. THIS INCLUDES UPREGULATION OF NUCLEAR COMPLEX GENES, AS WELL AS GENES FOR CYTOPLASMIC PROTEINS AND WNT LIGANDS AND THEIR COGNATE RECEPTORS. IN ADDITION, EPIGENETIC SILENCING OF SEVERAL NEGATIVE REGULATORS OF THE WNT PATHWAY HAVE BEEN IDENTIFIED. THE BALANCE BETWEEN EPIGENETIC DOWNREGULATION OF NEGATIVE EFFECTOR GENES AND INCREASED EXPRESSION OF POSITIVE EFFECTOR GENES DEMONSTRATE THAT THE EPIGENETIC DOWNREGULATION OF WNT ANTAGONISTS IS ONE MECHANISM, PERHAPS THE MAIN MECHANISM, THAT IS PERMISSIVE TO ACTIVE WNT SIGNALING IN CHRONIC LYMPHOCYTIC LEUKEMIA. MOREOVER, CONSTITUTIVE ACTIVATION OF THE WNT NETWORK AND TARGET GENES IS LIKELY TO IMPACT ON ADDITIONAL INTERACTING SIGNALING PATHWAYS. BASED ON PUBLISHED STUDIES, WE PROPOSE A MODEL OF WNT SIGNALING THAT INVOLVES MAINLY PERMISSIVE EXPRESSION, AND SOMETIMES OVEREXPRESSION, OF POSITIVE EFFECTORS AND DOWNREGULATION OF NEGATIVE REGULATORS IN THE NETWORK. IN THIS MODEL, DNA METHYLATION, HISTONE MODIFICATIONS AND ALTERED EXPRESSION OF MICRORNA MOLECULES INTERACT TO ALLOW CONTINUOUS WNT SIGNALING. 2010 20 3062 36 GENOME-WIDE DNA METHYLATION ANALYSIS REVEALS NOVEL EPIGENETIC CHANGES IN CHRONIC LYMPHOCYTIC LEUKEMIA. WE CONDUCTED A GENOME-WIDE DNA METHYLATION ANALYSIS IN CD19 (+) B-CELLS FROM CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) PATIENTS AND NORMAL CONTROL SAMPLES USING REDUCED REPRESENTATION BISULFITE SEQUENCING (RRBS). THE METHYLATION STATUS OF 1.8-2.3 MILLION CPGS IN THE CLL GENOME WAS DETERMINED; ABOUT 45% OF THESE CPGS WERE LOCATED IN MORE THAN 23,000 CPG ISLANDS (CGIS). WHILE GLOBAL CPG METHYLATION WAS SIMILAR BETWEEN CLL AND NORMAL B-CELLS, 1764 GENE PROMOTERS WERE IDENTIFIED AS BEING DIFFERENTIALLY METHYLATED IN AT LEAST ONE CLL SAMPLE WHEN COMPARED WITH NORMAL B-CELL SAMPLES. NINETEEN PERCENT OF THE DIFFERENTIALLY METHYLATED GENES WERE INVOLVED IN TRANSCRIPTIONAL REGULATION. ABERRANT HYPERMETHYLATION WAS FOUND IN ALL HOX GENE CLUSTERS AND A SIGNIFICANT NUMBER OF WNT SIGNALING PATHWAY GENES. HYPOMETHYLATION OCCURRED MORE FREQUENTLY IN THE GENE BODY INCLUDING INTRONS, EXONS, AND 3'-UTRS IN CLL. THE NFATC1 P2 PROMOTER AND FIRST INTRON WAS FOUND TO BE HYPOMETHYLATED AND CORRELATED WITH UPREGULATION OF BOTH NFATC1 RNA AND PROTEIN EXPRESSION LEVELS IN CLL SUGGESTING THAT AN EPIGENETIC MECHANISM IS INVOLVED IN THE CONSTITUTIVE ACTIVATION OF NFAT ACTIVITY IN CLL CELLS. THIS COMPREHENSIVE DNA METHYLATION ANALYSIS WILL FURTHER OUR UNDERSTANDING OF THE EPIGENETIC CONTRIBUTION TO CELLULAR DYSFUNCTION IN CLL. 2012